The invention relates to a magnetic or solenoid valve, on the movable armature of which is attached the valve disk that is acted upon by a restoring spring, and the magnet coil of which has a pickup winding with a high electrical capacity for opening or closing the valve, and a holding winding, the capacity of which is designed to hold the valve disk in a position where it is raised from the valve seat when the valve is open, and hold the valve disk in a position where it rests against the valve seat when the valve is closed.
The magnet coil in such solenoid valves encompasses a pickup winding and a holding winding with center tap. The pickup winding must be designed with high electrical capacity in order to actuate the magnet armature and thus the valve disc with substantial force in the opening and closing direction of the valve to open and close the solenoid valve. Once the valve has been opened or closed, there is a switch to holding capacity, which is sufficient to hold the valve disc in the open or closed position. DE 43 07 878 A1, which concerns such a solenoid valve, reports that it is known from DE 38 24 545 A1 in a contactless switching arrangement to insert in the feed line to the coil a parallel switch from a capacitor and a resistor, whereby when turned on, that is, for the pickup phase, there is a brief, distinct increase in the starting current corresponding to the capacitor capacity.
The object of the invention is to provide a solenoid valve in which the electrical control power can be reduced using simple means, especially when opening and closing the solenoid valve.
The solenoid valve of the present invention is characterized primarily in that the magnet coil comprises a pickup winding and a holding winding with a center tack, in that for opening and closing a capacitor is respectively connectable to a line branch leading to the pickup winding and to a branch leading to the center tap, and in that a DC/DC converter is disposed upstream of the capacitor such that the capacitor can be switched between a state where it is connected to the converter and a state where it is connected to the pickup winding. These features serve to realize this object. Thus it is possible to assure reliable opening and closing of the solenoid valve using simple circuit engineering means in that the pickup current or pickup capacity is taken from the capacitor, depending on the mechanical design of the solenoid valve either during opening of the valve or closing thereof, while subsequently only a small holding current must be taken from the connected consumer power supply. For the period in which the capacitor is charging a small charging current is also required that is not needed once the capacitor has been charged.
Pursuant to a preferred embodiment of the invention, a timer is provided for switching from pickup current operation to holding current operation, wherein the pickup winding and the holding winding are in series and the enter tap line branch is interrupted.